Cell surface glycosyltransferases have been found on cells from many, diverse sources. In several of these cases, they seem to be able to interact with glycoconjugates on apposing cells giving rise to stable complexes that could be one of the bases for intercellular adhesive specificity. Additionally, some of these complexes seem relatively unstable in that the nascent catalysis often is carried to completion. A rapidly growing body of data indicates that transformed cells are less able to carry out these surface reactions than are their non-transformed counterparts. This deficiency might be related to the lack of growth control shown by malignant cells in culture. We propose to critically test this potentially important hypothesis through four series of experiments: 1. Solubilization and purification of a surface transferase. These studies will allow the selection of enzyme deficient cell lines as well as the determination of the origin and location of the enzymes. 2. Correlations between malignancies and transferase activities. Through the use of clones and temperature-sensitive viral transformants, we will examine the relationship between growth control, spontaneous glycosylation in vitro and contact-dependent glycosylation. 3. Forced growth control by surface glycosylation. If surface glycosylation is related to growth cessation, this should be demonstrable by glycosylating cells that would not normally glycosylate themselves. Cells treated in such a manner should show a growth decrease compared to controls. 4. Isolation of a galactosyltransferase from fetuin. We have isolated and purified a UDPgalactose: N-acetylglucosamine galactosyltransferase from commercial fetuin. This enzyme appears to have much of the biological activity previously attributed to fetuin. Rigorous studies with this enzyme will be done in order to establish this point or rule it out.